The invention relates to a process and device for detecting saturation of a motion vector field.
Frame frequency conversion, for example during a conversion of standard, generally calls upon two processes:
                motion estimation which yields a vector field faithful to the spatio-temporal evolution of the objects constituting the scene,        interpolation which may make use of this vector field to correctly position the objects in an intermediate frame to be constructed.        
Motion-compensated interpolations, applied conventionally in frame frequency conversion, are not always suitable for all the situations encountered in a video sequence. The motion estimators and the associated interpolators do not support unlimited amplitudes of motion vectors. Constraints of hardware construction or even software constraints require that maximum operating values be fixed. Beyond these values, the procedures give rise to malfunctions.
The problem is therefore to evaluate the degree of confidence that can be accorded to a motion vector field in order to obtain interpolated images of good quality. Taking account merely, for such an evaluation, of the number of motion vectors of the vector field, whose level corresponds to the saturation threshold, is not sufficient. It does not make it possible to obtain interpolated images of good quality in numerous configurations, for example during large motions of objects of small dimension in the image.